How to use the magnetic field of a straight wire calculator
Find magnetic field at a distance from a current-carrying wire. Enter current, distance in the fields above; the magnetic field is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- I — Current (A)
- r — Distance (cm)
Worked example
With current = 10 A, distance = 5 cm, the calculator gives magnetic field ≈ 40 µT.
Frequently asked questions
What is the formula for the magnetic field of a straight wire calculation?
Magnetic field (µT) = MU0 × I / (2 × π × r / 100) × 1e6. Here I is current (A), r is distance (cm).
What inputs do I need for the magnetic field of a straight wire calculator?
You need current in A, distance in cm. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.